Why do diamonds turn yellow?

Answer 1

A diamond can appear to turn black if the diamond and mounting are not thoroughly cleaned before being heated by a jeweler. Dirt and debris between the diamond and the mount can burn and coat the bottom of the diamond with soot.

Answer 2

They turn yellow because of bad water... Here is what I do to clean this problem, I use alternating baths in a pickle solution (heated acid bath) and heated ultrasonic along with a steam cleaner to help steam out any particles etc. This process takes patience, as it takes much more time and repeated cycles of the process than an ordinary cleaning.

You could maybe try some more soaking in vinegar or even a CLR (calcium,lime rust) type cleaner as long as it does not have any chlorine in it (bad for gold)

Answer 3

A variety of factors are responsible for creating colored diamonds:

* Trace chemical elements in the crystal. For example, nitrogen produces yellow diamonds, boron produces blue ones. * Naturally occurring radiation (produces green diamonds). * Extreme pressure during the crystal's formation. This is thought to be responsible for producing the unique champagne, cognac and chocolate brown diamonds found in the Argyle diamond mine in Australia as well as for creating pink and rare red diamonds. Colored diamonds can also be produced by artificial means including irradiation (used to create black, blue, brown, red, green and other color diamonds) or high pressure/high temperatures (lightens and enhances existing color).

CVD (chemical vapor deposition) coatings are also sometimes used to produce artificially colored diamonds, but this is considered inferior as the coloring can be damaged by cleaners and chemicals.